The 42-year-old rider for trainer Kenny McPeek was breezing unraced 2-year-old New York Harbor when the horse fell about a sixteenth of a mile before the finish line at around 5:45 a.m. Saturday.

A release from the track states that emergency medical personnel who treated Acuna believe he died instantly from the spill. Track officials and veteran horsemen believe his death was Churchill Downs' first from a training accident in several decades, the release added.

McPeek called Acuna "one of the hardest working guys you'd ever meet." Training ceased after the accident and a moment of silence for the rider was held before Saturday's first race. Funeral arrangements are pending.

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